So I’m aware of the gambler’s fallacy. If an event has a set probability of happening and hasn’t happened yet, that doesn’t mean it’s *due* and now more likely to happen. Just because the coin landed on heads just now doesn’t mean it’s more likely to land on tails the next time.
So intuitively we could think just because an earthquake hasn’t happened in a while doesn’t mean it’s “overdue” and increasingly likely to happen in the future.
BUT, it’s my understanding that part of what causes earthquakes is a buildup of tension in the tectonic plates, which builds and builds until it’s finally too much to bear and there’s a sudden jerking motion as the plates snap or slip or whatever, and resettle to new positions, resulting in an earthquake. So if tension is always building up, does that mean for every day we don’t have an earthquake, the *next* day is more likely to have one?
In: 4
Yes, earthquakes become more likely the longer there isn’t one.
The gambler’s fallacy applies to *independent* events…the probability of a thing happening doesn’t depend on what happens before. The system has no “memory”.
That’s not true for earthquakes; as you note, they’re caused by built-up stress in the tectonic plates. An earthquake relieves at least some of the stress, so prior earthquakes *do* influence the conditions for future ones, the system has “memory”, and the events are NOT independent so gambler’s fallacy doesn’t apply.
This is part of the reason the Pacific NorthWest in N. America is getting a bit freaked out about “the big one”…the fault up there hasn’t slipped in any major way for several hundred years. All that stress that gets relieved in California every time they have an earthquake is still locked in in Oregon/Washington/British Columbia, which is making it more and more likely that an earthquake will happen and that it will be big when it does.
Edit: clarified that the fault in the Pacific NW isn’t the same as the one in California
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